基于表面等离子体激元的滤波器与解波分复用器理论研究

发布时间：2018-06-02 23:29

本文选题：表面等离子体激元 + 滤波器　；参考：《西南大学》2017年硕士论文

【摘要】：表面等离子体激元是一种沿着金属-介质界面传播的电磁表面波,由于其表面增强和高度局域的特性,使得人们得以克服衍射极限,在亚波长尺度的金属微结构中实现对光的传导和操控。目前,表面等离子体激元的理论研究趋于成熟,逐渐形成完善的学科,并在集成光学领域占有关键的一席之地。基于表面等离子体激元的应用研究也已在多个领域取得突破进展,包括集成波导、生物传感检测、纳米光刻、数据存储和新型光源等,从而极大地提升了光子器件的性能和光学回路的集成度。本文旨在帮助推进纳米尺度下光波的操控和光子器件设计,因此,基于表面等离子体激元在集成波导方面的研究,我们提出一类新型的滤波器和解复用器。本论文主要的研究内容如下:首先,根据金属的Drude模型,基于麦克斯韦方程组,理论分析了表面等离子体激元的色散特性,并介绍了表面等离子体激元的四个特征参数,以及根据波矢匹配在金属表面将表面等离子体激元激发出来的方法。接着,介绍金属-绝缘体-金属(Metal-Insulator-Metal,MIM)波导结构的原理和性质。其次,简要分析了本论文用到的研究方法,介绍了时域有限差分方法(Finite-Different Time-Domain,FDTD)的实现原理、激励源设定、稳定性要求和边界条件等,并结合FDTD仿真软件,对边耦合和肩耦合这两种谐振腔结构的耦合模理论做了阐述,分析验证了它们的传输和反射特性。然后,基于交叉形MIM波导的传输特性,我们将其与一组六边形谐振腔耦合,设计出一种新型的滤波器结构。该结构中,两条MIM波导相互正交,构成一个输入端口和三个输出信道。耦合模理论分析显示,通过调整不同信道间的表面等离子体波之间的相位,可以使得滤波信道中的传输效率达到峰值。而这一过程可以直接通过调节谐振腔的位置来容易地实现。我们采用FDTD仿真对理论分析进行了验证,此外,仿真显示在该结构中,通过调节耦合距离可以优化传输效率和线宽,还可以调节腔体的边长和填充介质来实现工作波长的调谐。最后,基于交叉波导上滤波器的理论研究,我们设计出一种新型的解波分复用器。该结构由一组十字交叉波导与三组六边形谐振腔构成,通过合理的布局,在三个信道中可以得到较为均衡的传输光谱,并最终得到较理想的传输效率和传输线宽,这说明该结构能成功实现波导交叉中的三端口解复用,对于构建复杂的光学系统和网络具有极大的应用潜力。
[Abstract]:Surface plasmon is a kind of electromagnetic surface wave propagating along the metal-dielectric interface. Due to its surface enhancement and highly localized characteristics, it is possible to overcome the diffraction limit. Light conduction and manipulation are realized in metal microstructures of subwavelength scale. At present, the theoretical research of surface plasmon has become mature, and gradually formed a perfect discipline, and plays a key role in the field of integrated optics. Applications based on surface plasmon have also made breakthroughs in many fields, including integrated waveguides, biosensor detection, nano-lithography, data storage and new light sources. Thus, the performance of photonic devices and the integration of optical circuits are greatly improved. The aim of this paper is to help promote the control of light waves and the design of photonic devices at nanometer scale. Therefore, based on the study of surface plasmon in integrated waveguides, we propose a new type of filter and demultiplexer. The main contents of this thesis are as follows: firstly, according to the Drude model of metals and Maxwell equations, the dispersion characteristics of surface plasmon are theoretically analyzed, and the four characteristic parameters of surface plasmon are introduced. And the method to excite the surface plasmon on the metal surface according to the wave vector matching. Then, the principle and properties of metal-insulator-MetalMIM) waveguide structure are introduced. Secondly, this paper briefly analyzes the research methods used in this paper, introduces the implementation principle of Finite-Different Time-Domain FDTD (Finite-Different Time-Domain FDTD), excitation source setting, stability requirements and boundary conditions, and combines with FDTD simulation software. The coupled mode theory of side-coupled and shoulder-coupled resonators is described and their transmission and reflection characteristics are analyzed and verified. Then, based on the transmission characteristics of cross-shaped MIM waveguides, we design a novel filter structure by coupling it with a group of hexagonal resonators. In this structure, two MIM waveguides are orthogonal to each other, forming one input port and three output channels. The coupling mode theory analysis shows that the transmission efficiency in the filtered channel can reach the peak by adjusting the phase between the surface plasma waves between different channels. This process can be easily realized by adjusting the position of the resonator directly. We use FDTD simulation to verify the theoretical analysis. In addition, the simulation shows that in this structure, the transmission efficiency and linewidth can be optimized by adjusting the coupling distance, and the wavelength tuning of the cavity can also be realized by adjusting the side length of the cavity and the filling medium. Finally, based on the theoretical study of filters on cross waveguides, we design a novel demultiplexer. The structure consists of a group of cross waveguides and three groups of hexagonal resonators. Through a reasonable arrangement, a more balanced transmission spectrum can be obtained in three channels, and an ideal transmission efficiency and transmission line width can be obtained. This shows that the structure can successfully realize the demultiplexing of three ports in waveguide crossing, and has great application potential for the construction of complex optical systems and networks.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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